CentOS7 Network Service开机无法启动的解决方法

CentOS7安装完成并配置好所有网络相关配置后重启机器，使用

$ systemctl --failed

检查是否有失败的服务

发现在network服务启动失败，使用systemctl status network查看服务状态，得到如下错误信息：

$ systemctl status network

Nov 23 22:09:07 hdcoe02 network[597]: Bringing up loopback interface:  Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:07 hdcoe02 network[597]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:08 hdcoe02 network[597]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:08 hdcoe02 network[597]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:08 hdcoe02 network[597]: [  OK  ]  
Nov 23 22:09:08 hdcoe02 network[597]: Bringing up interface enp0s25:  Error: Connection activation failed: Connection 'enp0s25' is not available on the device enp0s25 at this time.  
Nov 23 22:09:08 hdcoe02 network[597]: [FAILED]  
Nov 23 22:09:08 hdcoe02 systemd[1]: network.service: control process exited, code=exited status=1  
Nov 23 22:09:08 hdcoe02 systemd[1]: Failed to start LSB: Bring up/down networking.  

设定开机启动一个名为NetworkManager-wait-online服务，命令为：

$ systemctl enable NetworkManager-wait-online.service

 重启network:

$ systemctl restart network